compare {
  position: relative;
  display: inline-block;
  overflow: hidden;
}

compare .before,
compare .after {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-size: cover; 
  background-position: center;
}

compare .slider {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 3px;
  background: #fff;
  border: 1px solid #000;
  cursor: ew-resize;
  z-index: 10;
}

compare .slider-handle {
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1.0;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: #000;
  color: #fff;
  font-size: 16px;
  font-family: monospace;
  border-radius: 10px;
  border: 2px solid #fff;
  box-shadow: 0 0 4px rgba(0,0,0,0.3);
  cursor: ew-resize;
  z-index: 20;
  user-select: none;
  width: 35px;
  height: 50px;
}